WO2002019547A2 - Method to reduce horizontal lifeline tension and extension during fall arrest - Google Patents
Method to reduce horizontal lifeline tension and extension during fall arrest Download PDFInfo
- Publication number
- WO2002019547A2 WO2002019547A2 PCT/US2001/027259 US0127259W WO0219547A2 WO 2002019547 A2 WO2002019547 A2 WO 2002019547A2 US 0127259 W US0127259 W US 0127259W WO 0219547 A2 WO0219547 A2 WO 0219547A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- line
- section
- load
- energy
- horizontal lifeline
- Prior art date
Links
Classifications
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
- A62B35/00—Safety belts or body harnesses; Similar equipment for limiting displacement of the human body, especially in case of sudden changes of motion
- A62B35/0043—Lifelines, lanyards, and anchors therefore
- A62B35/0056—Horizontal lifelines
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
- A62B35/00—Safety belts or body harnesses; Similar equipment for limiting displacement of the human body, especially in case of sudden changes of motion
- A62B35/04—Safety belts or body harnesses; Similar equipment for limiting displacement of the human body, especially in case of sudden changes of motion incorporating energy absorbing means
Definitions
- the present invention relates to a method for reducing line tension and extension in horizontal lifelines used for fall arrest anchorages. Additionally, this invention relates to a method that can be used to determine total energy capacity of a horizontal lifeline system and the safety factors that can be used for design. Additionally, this invention relates to the method used to predict line tension and extension as input loads and span lengths change.
- Horizontal lifelines are sections of cable or other elongated, usually flexible, members that are used as an attachment structure for tethers that are in turn attached to safety harnesses and the like.
- the safety harness type device is a device worn by an individual working at an area where the risk of falling is a significant risk.
- Horizontal lifeline systems are currently used in many applications for fall arrest anchorages in the manufacturing, processing, transportation, and construction and other industries. These horizontal lifelines may be installed as permanent systems for such applications as pipe racks, loading docks, and hangar facilities; portable systems for such applications as construction; and temporary systems for such applications as maintenance or rescue.
- a typical installation for a horizontal lifeline system is to suspend a horizontal cable between two anchorages, typically from 20-ft. to 200-ft. apart.
- the anchorage elevation is typically 5-ft. above the walking/working surface as is required by geometry restrictions imposed by OSHA regulations.
- a horizontal lifeline When suspended, a horizontal lifeline must be pre-tensioned to keep the line from having too much sag in the center of the span.
- the angle that the cable makes at each anchorage, measured below horizontal, is referred to as the "Sag Angle".
- This tension is proportional to the angle of sag.
- the load amplification factor For example, at 0.5° of sag the load amplification factor is approximately 50 to 1. At 7° of sag the load amplification is approximately 4 to 1.
- the load amplification increases exponentially with decreases in sag angle. For this reason, most horizontal lifeline installations use only enough pre-tension, or tension load in the lifeline, so that the cable can maintain a sag in the 7° range when loaded.
- This amount of pre-tension is indicated by the manufacturers and is usually in the 175 to 300-lb. Range, depending on span length and cable weight .
- the present invention generally relates to a new technology referred to as "Cable Tuning" that can be used to increase the safety of workers using horizontal lifelines.
- Horizontal lifeline installations were limited by 2 factors - acceptable line tension and acceptable total fall distances. Usually to decrease line tension one had to allow a longer fall distance or (more time) to absorb the fall energy. Conversely, if one was limited by fall distance, it required higher allowable line tensions to absorb the energy in a shorter fall distance (or in less time) .
- the method included analysis of the following components: a. a shock absorber with integral line tension indicator; b. a horizontal lifeline cable; c. end anchorages; d. a line tensioner; e. a method to determine input energy; f . a method to determine shock absorber energy capacity; g. a method to determine shock absorbing lanyard energy capacity; h. a method to determine horizontal lifeline energy capacity; i. a method to determine horizontal lifeline strain under tension.
- the invention relates to a method for explaining quantitatively how horizontal lifeline rope absorbs energy and a method for calculating its' total energy capacity.
- Detail A is a drawing of a typical horizontal lifeline system.
- Detail B is a drawing of a typical HLL system after deployment .
- Figure 2 is a HLL force balance diagram.
- Figure 3 contains 2 details:
- Detail A shows an HLL shock absorber stress-strain curve.
- Detail B shows a shock absorbing lanyard stress-strain curve .
- Figure 4 contains 2 details:
- Detail A shows a tension-strain diagram for a horizontal lifeline steel cable with 1 man fall energy.
- Detail B shows a tension-strain diagram for a horizontal lifeline steel cable with 4 men fall energy.
- Figure 5 contains 2 details:
- Detail A shows a tension-strain diagram for a non-pre- tensioned steel cable.
- Detail B shows a tension-strain diagram for a pre-tensioned (Tuned) steel cable. Best Mode for Carrying Out the Invention
- Figure 1 illustrates a horizontal lifeline arrangement and geometry used according to the preferred embodiment of this invention.
- the horizontal lifeline cable (2) is inline with the line tensioner (4) , and the horizontal lifeline shock absorber (6) .
- the horizontal lifeline system is supported by end anchorages (8) .
- the worker (10) is shown on the walking/working surface (12) .
- the horizontal lifeline (2) is shown extended, as it would be after a fall has occurred.
- the initial sag angle ⁇ . has
- the total fall distance required to stop and suspend the worker (10) is shown by (TFD) . This is the distance that the worker (10) has fallen from the walking/working surface (12) to the lowest point in the fall cycle.
- the worker (10) is connected to the horizontal lifeline using a shock absorbing vertical lanyard (14) or possibly a self- retracting lanyard.
- the energy that the worker has imparted into the system is calculated as follows.
- E IN W x D or the input energy into the system is equal to the workers ' weight times the distance the worker falls.
- a 3 . 5° drop angle on a 20-ft . span means a drop elevation of :
- the final line, or lifeline, tension is reduced.
- This approach runs counter to the theory endorsed by know or conventional lifeline technology, which states that final line tension is determined by initial sag angle, and that the greater the sag angle, the lower the final line tension.
- the disclosed invention takes advantage of the discovery that final line tension is predominantly determined by the momentum gained by the falling object, and not the inclusion of a large sag angle in the resting line.
- the horizontal lifeline shock absorber (6) 3.
- the energy capacity of the horizontal lifeline shock absorber (Item 6 in Figure 1) is determined by the extension force and the extension distance.
- the extension force is 2300-lb. and the extension distance is 5.25".
- the energy capacities of the inline horizontal lifeline shock absorber and the shock-absorbing lanyard were both determined by the simple calculation of force times distance because the force is constant through the distance it acts. Additionally, both of these shock absorbers are all mechanical hysterisis devices, meaning that they convert all of the input energy into heat and mechanical deformation and return none to the system.
- the HLL cable on the other hand has a variable input force that increases linearly with strain and has almost no hysterisis and returns virtually all of the energy it absorbs back to the system.
- Tuning cable provides several important benefits for horizontal lifeline systems.
- HLL systems require 150 to 300-lb. of pre-tension to suspend the cable at the proper sag angles .
- Cable tuning requires much higher tensions, typically in the 1000 to 2000-lb. range.
- the cost to the system of cable tuning is that one gives up or reduces total energy capacity to achieve lower line tension and strain. But in terms of total energy capacity a reduction of merely 1% can make significant reductions in HLL tension and total fall distance.
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- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Emergency Lowering Means (AREA)
- Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)
- Jib Cranes (AREA)
- Conveying And Assembling Of Building Elements In Situ (AREA)
- Details Of Television Scanning (AREA)
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA002439825A CA2439825C (en) | 2000-08-31 | 2001-08-30 | Method to reduce horizontal lifeline tension and extension during fall arrest |
AU2001288636A AU2001288636A1 (en) | 2000-08-31 | 2001-08-30 | Method to reduce horizontal lifeline tension and extension during fall arrest |
DE60131467T DE60131467T2 (en) | 2000-08-31 | 2001-08-30 | METHOD FOR REDUCING TENSION OF HORIZONTAL SAFETY LENGTH AND EXTENSION DURING THE FALL STOP |
EP01968384A EP1399223B1 (en) | 2000-08-31 | 2001-08-30 | Method to reduce horizontal lifeline tension and extension during fall arrest |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US22971900P | 2000-08-31 | 2000-08-31 | |
US60/229,719 | 2000-08-31 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2002019547A2 true WO2002019547A2 (en) | 2002-03-07 |
WO2002019547A3 WO2002019547A3 (en) | 2004-01-15 |
Family
ID=22862423
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2001/027259 WO2002019547A2 (en) | 2000-08-31 | 2001-08-30 | Method to reduce horizontal lifeline tension and extension during fall arrest |
Country Status (7)
Country | Link |
---|---|
US (1) | US6581725B2 (en) |
EP (1) | EP1399223B1 (en) |
AT (1) | ATE378092T1 (en) |
AU (1) | AU2001288636A1 (en) |
CA (1) | CA2439825C (en) |
DE (1) | DE60131467T2 (en) |
WO (1) | WO2002019547A2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2853250A1 (en) * | 2003-04-07 | 2004-10-08 | Richard Lebraut | Safety line for steeplejack has cable tensioned between anchors with sprung damper having controlled release of springs at set load |
WO2007116202A1 (en) * | 2006-04-11 | 2007-10-18 | Maxess Limited | Safety line apparatus |
Families Citing this family (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6811202B2 (en) * | 2001-04-12 | 2004-11-02 | B. C. Hornady | Apparatus for covering payloads |
US20050092546A1 (en) * | 2003-11-04 | 2005-05-05 | Hsu Samuel W. | Safety belt device having warning device |
US7237650B2 (en) * | 2004-05-19 | 2007-07-03 | D B Industries, Inc. | Tension device for use with a self-retracting lifeline |
GB0525386D0 (en) * | 2005-12-13 | 2006-01-18 | Dawson Brian | Safety harness |
EP2195208A1 (en) * | 2007-09-05 | 2010-06-16 | Leigh Dowie | Fall arrest assembly |
US10072689B2 (en) * | 2008-02-06 | 2018-09-11 | Honeywell International, Inc. | Stanchion systems, stanchion attachment systems, and horizontal lifeline systems including stanchion systems |
DE102008008577A1 (en) * | 2008-02-11 | 2009-08-13 | Lufthansa Engineering And Operational Services Gmbh | fall Protection |
GB2472879A (en) * | 2009-08-21 | 2011-02-23 | Reliance Ind Llc | Attachment assembly for securing an object to a lanyard |
US8701826B2 (en) * | 2010-09-21 | 2014-04-22 | Honeywell International Inc. | Shock absorbing lanyard |
CA2765986C (en) * | 2011-01-28 | 2015-03-24 | Tuffbuilt Products Inc. | Apparatus for receiving shock loading |
GB2512064B (en) * | 2013-03-18 | 2018-05-23 | Latchways Plc | Tether System for a Safety Line |
US10060146B2 (en) | 2014-04-07 | 2018-08-28 | Conxtech, Inc. | I-beam-attachable lifeline system |
US10828517B2 (en) * | 2017-08-16 | 2020-11-10 | Honeywell International Inc. | Smart fall arrest system |
US10449399B2 (en) * | 2017-09-14 | 2019-10-22 | Werner Co. | Horizontal lifeline system and method of adjusting a horizontal lifeline system |
US10512802B2 (en) * | 2017-10-20 | 2019-12-24 | Werner Co. | Energy absorber cover and horizontal lifeline system including the same |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5332071A (en) * | 1993-03-09 | 1994-07-26 | Sinco Incorporated | Shock absorber for safety cable system |
US5458218A (en) * | 1992-12-16 | 1995-10-17 | Hemscheidt Fahrwerktechnik Gmbh & Co. Kg | Suspension system for motor vehicles as well as damping valve for said suspension system |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1994008658A1 (en) * | 1992-10-14 | 1994-04-28 | Rose Systems, Inc. | Safety apparatus |
US5957432A (en) * | 1997-10-23 | 1999-09-28 | Ostrobrod; Meyer | Safety apparatus for horizontal lifeline |
WO1999051304A2 (en) * | 1998-04-02 | 1999-10-14 | Choate, Gary, A. | Energy absorption device for fall arrest systems |
-
2001
- 2001-08-30 US US09/944,279 patent/US6581725B2/en not_active Expired - Lifetime
- 2001-08-30 DE DE60131467T patent/DE60131467T2/en not_active Expired - Lifetime
- 2001-08-30 AU AU2001288636A patent/AU2001288636A1/en not_active Abandoned
- 2001-08-30 CA CA002439825A patent/CA2439825C/en not_active Expired - Lifetime
- 2001-08-30 EP EP01968384A patent/EP1399223B1/en not_active Expired - Lifetime
- 2001-08-30 WO PCT/US2001/027259 patent/WO2002019547A2/en active IP Right Grant
- 2001-08-30 AT AT01968384T patent/ATE378092T1/en not_active IP Right Cessation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5458218A (en) * | 1992-12-16 | 1995-10-17 | Hemscheidt Fahrwerktechnik Gmbh & Co. Kg | Suspension system for motor vehicles as well as damping valve for said suspension system |
US5332071A (en) * | 1993-03-09 | 1994-07-26 | Sinco Incorporated | Shock absorber for safety cable system |
Non-Patent Citations (1)
Title |
---|
See also references of EP1399223A2 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2853250A1 (en) * | 2003-04-07 | 2004-10-08 | Richard Lebraut | Safety line for steeplejack has cable tensioned between anchors with sprung damper having controlled release of springs at set load |
EP1466650A1 (en) * | 2003-04-07 | 2004-10-13 | Lebraut, Ronan | Lifeline with fall absorber |
WO2007116202A1 (en) * | 2006-04-11 | 2007-10-18 | Maxess Limited | Safety line apparatus |
Also Published As
Publication number | Publication date |
---|---|
CA2439825A1 (en) | 2002-03-07 |
DE60131467T2 (en) | 2008-09-04 |
US20020046902A1 (en) | 2002-04-25 |
CA2439825C (en) | 2009-05-26 |
EP1399223B1 (en) | 2007-11-14 |
EP1399223A2 (en) | 2004-03-24 |
DE60131467D1 (en) | 2007-12-27 |
US6581725B2 (en) | 2003-06-24 |
EP1399223A4 (en) | 2006-04-19 |
ATE378092T1 (en) | 2007-11-15 |
AU2001288636A1 (en) | 2002-03-13 |
WO2002019547A3 (en) | 2004-01-15 |
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